Pour point depressor



United States Patent 3,325,408 POUR POINT DEPRESSOR Stephen J. Wayo, Whiting, Ind, assignor to Sinclair Research, Inc., New York, N.Y., a corporation of Delaware No Drawing. Filed Sept. 16, 1963, Ser. No. 309,325

6 Claims. (Cl. 252-57) This invention relates to a composition for improving the pour point characteristics of mineral oil bases to permit their flow at low temperatures. More particularly the present invention relates to a pour point depressor comprising the reaction product of an unsaturated monoester and an aroma-tic hydrocarbon.

It has now been found that the condensation product of polyunsaturated monoesters and an aromatic hydrocarbon when added in small amounts to mineral oils substantially reduces the pour point of mineral oil. The polyunsaturated esters may be represented by the formula:

wherein R is an olefinic hydrocarbon radical of about 11 to 25 carbon atoms, preferably about 15 to 19 carbon atoms, and R is an olefinic hydrocarbon radical of about 12 to 26 carbon atoms, preferably about 16 to 20 carbon atoms. It is important to note that the ester contains at least one double bond in each of the acid and alcohol residues. Esters in which either the acid or alcohol residue issaturated, as for instance glycerides or ester mixtures composed essentially of glycerides, on condensation with aromatic hydrocarbons do not form the effective pour depressors of the instant invention. Suitable aliphatic acids that may be used include the natural mono-unsaturated acids such as hypogeic, oleic, eladic, erucic and brassidic and polyunsaturated acids such as linoleic acid and linolenic acid. Preferably the acid does not contain more than two olefinic bonds.

Suitable alcohols for use in preparing the monoesters are the monohydric, unsaturated aliphatic, including cy. cloaliphatic, alcohols. The alcohols may be primary, secondary or tertiary and may contain one or more carbon-to-carbon double bonds. The preferred class of alcohols are the primary and secondary monohydric, aliphatic unsaturated alcohols which contain about 12 to 26 carbon atoms. Examples of suitable alcohols include octene- 3-01-8, decene-l-ol-lO, oleyl alcohol, erucyl alcohol, lino leyl alcohol, cetenyl alcohol, eicosene-lO-ol-l, citronellol, and the like. The preferred alcohol contains at least 12 carbon atoms and not over 22, and is mono or diolefinic in character.

The following monoesters are typical and illustrative of the general class that are suitable in the condensation reaction: decylene oleate, dodecylene oleate, pentadecylene oleate, oleyl oleate, eicosyline linoleate, emcyl erucate, linolenyl erucidate, etc. Naturally-occurring oil containing essentially a mixture of monoesters such as sperm oil, jojoba oil, etc., may also be used. It is known that sperm oil is a mixture of mono-esters of unsaturated fatty acids of the oleic series and of monohydric alcohols of the ethylene series. The principal and characteristic components of sperm oil are monoesters which are unsaturated, i.e., contain double bonds, on each side of the ester group. If desired, the esters may be substituted with non-interfering substituents.

The aroma-tic hydrocarbon may be chosen from a Wide variety of aromatic compounds including mono and polycyclic aromatic hydrocarbon compounds which correspond to the general formula:

3,325,408 Patented June 13, 1967 wherein R forms a fused aromatic hydrocarbon ring, preferably R is C,H f indicates the fused ring relationship (two carbon atoms common to two aromatic nuclei, e.g., as in naphthalene); and m is 0 to 2. The aromatic ring and R may be substituted with other radicals such as alkyl and phenyl groups which do not prevent the desired reaction. Particularly preferred aromatic hydrocarbons are benzene and naphthalene.

The condensation products of the present invention can be prepared, for example, by subjecting a mixture of about 0.2 to 2 moles of the aromatic hydrocarbon per mole of the polyunsaturated ester, preferably about 0.5 to 1.5 moles of the aromatic hydrocarbon per mole of the ester, to a condensation temperature, usually about 25 to 125 C., preferably about 45 to C. in the presence of a Friedel-Crafts catalyst such as aluminum chloride, aluminum bromide, titanium tetrachloride, boron trifluoride, etc. The preferred catalyst is aluminum chloride. The weight proportions of aromatic-unsaturated monoester mixture to catalyst employed may be about 1 'to 10 parts of the mixture to 1 part of catalyst or preferably about 2 to 5 parts of the mixture to 1 part of catalyst. If desired, inert liquid hydrocarbon diluents, e.g., petroleum distillates, alkanes and aromatics (if used under non-reactive conditions), preferably of 5 to 12 carbon atoms such as hexane, may also be employed. When used, the liquid diluent or solvent is generally present in the range of about .05 to 10 or more, preferably about 0.5 to 3, volumes of diluent to 1 volume of the unsaturated monoester. The resulting solution of the pour depressor may be used as such.

A preferred method of preparation comprises adding equimolar amounts of the polyunsaturated ester and aromatic compound to a reaction vessel and stirring the mixture until the aromatic compound is dispersed. With continued stirring the Friedel-(Irafts catalyst is then added portionwise, the rate of addition being such that the desired reaction is attained and maintained. On completion of the reaction, a liquid C C hydrocrabon solvent or a mixture thereof is then added in an amount sulficient to reduce the viscosity of the reaction product mixture to the point where it can be readily Withdrawn and further processed. The solution is then treated with an acid solution to decompose the catalyst complex formed and the resulting solution washed with water, dilute aqueous caustic soda, or by other suitable washing methods. The solvent may or may not be removed but it i preferred to employ a solvent that need not be removed, that is, having chemical and physical properties compatible with those of the mineral oils into which it is to be added. In

the latter case, the product is obtained as a concentrate solution, more conveniently useable. Solvents which in general need not be removed are, for example, C to C liquid alkanes, including cycloalkanes, or mixtures thereof. A process variation, which may be preferred in this method is the addition of an inert low-boiling liquid hyrocarbon diluent, preferably one that need not be removed as aforedescribed, to the ester-aromatic mixture before the addition of the aluminum halide catalyst.

The active reaction products from the condensation reaction are oil soluble, acetone insoluble, normally liquid reaction products boiling essentially above about 200 F. at 1 mm. Hg. If desired the product can be separated from the total reaction mixture as by vacuum distillation but it can conveniently be employed in admixture with any unreacted material and other lighter products that may be present in the reaction mixture or otherwise diluted as with lighter hydrocarbons to form an additive concentrate.

Among the mineral oil bases which constitute the major amount of the composition are normally liquid 3 petroleum oils boiling primarily above the gasoline range and include, for instance, lubricating oils, diesel fuels, fuel oils, etc. These oils are usually petroleum middle distillates and commonly have relatively high pour points, for instance at least about l F. or higher. The oils can be in their relatively crude state or they can be treated in accordance with well-known commerical methods such as acid or caustic treatment, solvent refining, clay treatment, etc. Fuel oils which can be improved by the condensation products of this invention include, for instance, hydrocarbon fractions boiling primarily in the range of about 300 to 750 F. The fuel oils can be ring was continued while the anhydrous aluminum chlo ride catalyst was added in increments, the addition being such that the temperature desired was attained. The stirring was continued until the reaction was substantially complete and a solvent (hexane or benzene) was added to reduce the viscosity of the reaction mixture to the point where it could be readily withdrawn. The resulting solution was then treated with an excess of aqueous HCl to decompose the aluminum chloride complex and the treated solution was washed with water until neutral. Unless otherwise indicated the solvent introduced was removed.

TABLE I.COPOLYMERIZATION OF AROMATIOS WITH POLYUNSA'IURATED ESTERS Run No 1 2 3 4 Corn Oil (grins) Sperm Oil (grms.) Linseed Oil (grins). Oleyl Oleate (grms). Benzene (grms.) Naphthalene (grins)- Phenol (grms) A1Cl Anhyd. (grms). n-Hexane (ml) Benzene (ml) Rcac. Temp, Max. 0.). Reac. Time, Max. (min) Product Yield (Wt. percent)". Iodine Value of Product Iodine Value of Oil Reactant.

1 Runs 2, 4 and 6, 45 N.W. Sperm Oil. Runs 7, 8, 9 and 10, 45 Winter Sperm Oil.

2 Isopropyl alcohol.

a In this run the A101 was added in two equal portions; after addition of the first portion the temperature rose to 4550 C., and was held there for 90 minutes and after addition of the second portion the temperature rose to 85-90 0., and was held there for minutes.

straight run distillate fuel oils or mixtures of straight run fuel oils, naphthas and the like with cracked distillate stocks. The cracked materials will frequently be about 15 to 70 volume percent of the fuel.

Lubricating oils which can be improved in their pour point characteristics normally have viscosities in the range of about 30 to 3000 SUS at 100 F. These mineral lubricating oils may be derived from a petroleum crude source, whether parafiinic, mixed or naphthenic in type, and may be refined by any of the refining techniques of the petroleum industry.

The minor amount of condensation product added to the base oils may be dependent upon the particular oil employed, but in all cases will be sufficient to reduce the pour point, often about 0.005 to 1% of the overall composition. More than 1% of the additive may be used especially if properties such as viscosity index are also to be improved. With lubricating base oils, the amounts used will generally fall in the range of about 0.05 to 1%, preferably about 0.1 to .75% by weight and with distillate fuels the amount added is usually in the range of about 0.005 to 0.1%, preferably about .01 to 0.1 weight percent of the total reaction product.

In addition to the condensation product of the instant invention the composition may contain as well, other additives commonly incorporated into mineral oils to improve their properties. Illustrative of these additives are antioxidants, corrosion inhibitors, foam inhibitors, detergents, viscosity index improvers, extreme pressure agents, etc.

The following examples are included to further illustrate the present invention.

Example I Several copolymers of the aromatics and unsaturated fatty materials shown in Table I were prepared according to the following general procedure employing the specific amounts and reaction conditions shown in Table 1.

The unsaturated fatty material and the aromatic compound were placed in a reaction vessel and the mixture stirred until the aromatic compound dissolved. The stir- The reaction products of Runs 2, 4, 6 and 7 were vacuum distilled at 0.1 mm. Hg to the bottoms fraction identified below:

Product Fractionation of Run 2 4 6 7 Overhead, (Wt. Percent) 55. 7 39.3 8.6 1 43.8 46. 7 Iodine Value 53.1 Bottoms (Wt. Percent). 41.7 60. 7 91. 4 1 53. 6 53.3 Iodine Value 29. 7 Mean Mol. Wt. 2,037 1, 284 1, 203

1 On total product. 2 Cryoscopic.

To fuel oils having their inspections reported in Table II were added various amounts of the bottoms of fractionations 2, 4, 6 or 7. Samples of fuel oil containing various amounts of the unfractionated reaction product of Runs 1, 2, 3, 4, 5, 8, 9 or 11 were also prepared as were samples of fuel containing various amounts of the overhead fraction from fractionation identified as Ohd 7. The additives which were the bottoms from the fractionation are identified in Table III with the letter A after the run number.

TABLE II.INSPEGTION TESTS ON No. 2 FUELS The pour points of each of the samples were taken and the results summarized in Table III below:

TABLE IIL-EVALUATION OF COPOLYMERS AS POUR DEPRESSANTS IN NO. 2 FUEL OILS Fuel A Pour Depressant Additive (P.D.) 2A 4A 6A 6B 7!. hd7 9 10 11 Ester Sperm Sperm Sperm Sperm Sperm Sperm Sperm Sperm Oleyl Oleate Aromatic Benzene Benzene Benzene Benzene Benzene Benzene Naphth Phenol Naphth.

Concentration (Wt. Percent):

one

Fuel B Fuel 0 Pour Depressant Additive 1 2A 3 4A 5 7A 7A Ester .1 Corn Sperm Linseed Sperm Linseed Sperm Sperm Aromatic Benzene Benzene Benzene Benzene Benzene Benzene Benzene P.D. Concentration (Wt. Percent):

None 0.005

The data show that the sperm oil-benzene, sperm oilnaphthalene and olcyl cleats-naphthalene condensation products were effective pour depressants in the fuel oils. However, the corn oil-benzene (Run 1) and linseed oil benzene (Runs 3 and 6) condensation products were inin Table IV. In the table, oils D, E and F are solventtreated Mid-Continent neutral oils and the oil G is 21 Mid- Continent bright stock. The oils have the following propertics:

effective as pour depressants, indicating that naturallyoccurring esters consisting essentially of glyccrides are D E F G not suitable as the ester component of the condensation G 3 r 9 1 r r r reaction. Also, the sperm oil-phenol condensation product {43533333333 5 2 55 1 .3 ZQS SUS at 100 F 155-165 195-210 600-650 2, 650 was ineifective as a pour depressant. I I fi 1%: H7. 5 6740 M in 95 Example 11 Color Max 1.5 1.5 an 7.0 Pour Max r 10 10 15 15 Various of the condensation products identified in Ex ample I above were evaluated as pour depressants and as viscosity iinprovers in several lubricating oils shown 50 The result of the te t are shown in Table IV.

TABLE IV Oil D OilE Oil G Pour Depressant 2A 4A 9 2A 4A Sample No 14037 14200 14020 14037 Sperm Sperm Sperm Sperm C6 C10 06 C10 Single Deoiled Foots Wax (Wt. percent) D 0 0 0 PD 0Concentration (Wt. percent):

EVALUATION OF OOPOLYMER AS A VI IMPROVER IN A LUB RICATING OIL KWIOO KV/210 VI Blend of 91 Vol. percent Oil E: 9 Vol. percent Oil F 48. 08 6. 502 92. 5 Blend of 91 Vol. percent Oil E: 9 Vol. percent Oil F plus 4.9

wt. percent Pour Depressant 9 53. 42 7. 141 100. 0

wherein R is an olefinic hydrocarbon radical of about 11 to 25 carbon atoms and R is an olefinic hydrocarbon radical of about 12 to 26 carbon atoms and an aromatic hydrocarbon having the general formula:

wherein R forms an aromatic hydrocarbon ring, indicates the fused ring relationship and m is 0 to 2, the molar ratio of the aromatic hydrocarbon to the monoester being about 0.2 to 2: 1, said condensation product boiling above about 200 F. at 1 mm. Hg.

2. The composition of claim 1 wherein the monoester is sperm oil and the aromatic hydrocarbon is naphthalene.

3. The composition of claim 1 wherein the monoester is sperm oil and the aromatic hydrocarbon is benzene.

4. The composition of claim 1 wherein the petroleum distillate oil is a petroleum distillate fuel oil boiling primarily in the range of about 300 to 750 F. and the amount of the condensation product added is about .01 to 0.10% by weight.

5. The composition of claim 1 wherein the petroleum distillate oil is a lubricating oil and the amount of the condensation product added is about 0.1 to .75% by Weight.

6. The composition of claim 1 wherein the monoester is oleyl oleate and the aromatic hydrocarbon is selected from the group consisting of benzene and naphthalene.

References Cited UNITED STATES PATENTS 2,061,593 11/1936 Robinson 260-398 X 2,106,247 l/1938 Gleason 25257 2,211,163 8/1940 Ries 25257 2,246,762 6/1941 Schirm 26039 8 X 2,355,616 8/1944 Barker 25257 2,992,987 7/1961 Fields 252 56 FOREIGN PATENTS 884,246 12/1961 Great Britain.

DANIEL E. WYMAN, Primary Examiner. W. H. CANNON, Assistant Examiner. 

1. A MINERAL OIL COMPOSITION HAVING IMPROVED POUR POINT PROPERTIES CONSISTING ESSENTIALLY OF A PETROLEUM DISTILLATE OIL BOILING ABOVE THE GASOLINE RANGE HAVING INCORPORATED THEREIN A SMALL AMOUNT SUFFICIENT TO IMPROVE THE POUR POINT OF THE PETROLEUM DISTILLATE OIL OF AN OIL-SOLUBLE, ACETONE INSOLUBLE, NORMALLY LIQUID CONDENSATION PRODUCT OF A POLYUNSATURATED MONOESTER HAVING THE GENERAL FORMULA: 